<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        /*子元素float，父元素的高度会坍塌
        怎样让父元素的高度回来
        */
        .parent{
            width: 200px;
            /*height: 100px;*/
            background: red;
            overflow: hidden;
        }
        .child{
            width: 100px;
            height: 100px;
            background: blue;
            float: left;
        }
        .two{
            width: 200px;
            height: 200px;
            background:yellow;
        }
    </style>
</head>
<body>
    <div class="parent">
       <div class="child">

       </div >  
    </div>
    <div class="two">

    </div>
</body>
</html>